This is book 7 of the "Young Wizards" series.

This note contains spoilers for the book.

This brings me up-to-date with the Wizard series. A simple holiday -- Nita and Kit go off on an exchange program, while Nita's father hosts three foreign wizards from different planets. Dairine is restricted to the Sol system; she initiated the applications to the exchange program without permission.

As the title might suggest, things don't work out that simply; both groups find major problems that they're just the right ones to fix. On the Earth end, they need to get authorization from the Galactic Arm coordinating wizard—because nobody below that in the hierarchy is available, they're all out on assignment. We never do learn what the emergency was that had all the top local wizards so tied up.

Nita manages to bind the Lone Power to a valid Oath, and they cooperate a bit, and once again survive (just barely).